Delta Motion has added a new trapezoid waveform command to its RMC motion controllers, providing machine builders and test engineers with a method for generating any type of trapezoid, triangle, sawtooth and square wave motion profile for both position and pressure or force control applications. This complements the sinusoidal and curve waveforms already offered by the RMC. Together, these commands allow engineers to select the waveform best suited to the application, from smooth sinusoidal motion and custom profiles to sharp-edged cyclic profiles with adjustable rise, high, fall and low segments.

The trapezoid waveform command generates continuous cyclic waveforms directly within the RMC controller, which is designed to eliminate the need to program individual motion segments or create custom waveform generators in a PLC. The waveforms are infinitely configurable using parameters including amplitude, offset, frequency and rise time, high time and fall time.

Waveform parameters can be modified while the command is running. Amplitude, offset, phase and waveform shape may all be changed on the fly without stopping the motion.

The command is available for both position control and pressure or force control, allowing engineers to generate cyclic position profiles or cyclic force profiles using the same command structure and programming methods.

For force-controlled applications, the waveform command supports adaptive amplitude control. Rather than commanding a fixed output, the adaptive control algorithm automatically adjusts waveform amplitude to maintain the requested peak force as system conditions change. This capability is designed for fatigue testing, material testing, durability testing and other applications where specimen stiffness or system dynamics vary over time.

The trapezoid waveform command also supports changing the waveform gradually over time. For example, the duty cycle of a square wave can be adjusted over a certain time or a number of cycles. The entire shape can be changed, such as a triangle changing to a sawtooth over a specified number of seconds or cycles (Figure 1).

Waveform generation is performed entirely within the RMC motion controller, allowing deterministic execution independent of PLC scan times or network update rates. This is designed to reduce application complexity while providing highly repeatable cyclic motion for testing and automation systems.

"Many of our product enhancements come directly from customer feedback, and the trapezoid waveform command is an example of this, a practical feature that simplifies application development with our RMC motion controllers," said Steve Nylund, CEO of Delta Motion.

Typical applications include fatigue testing, hydraulic and electromechanical material testing machines, component durability testing, production cycle simulation, actuator characterization and other applications requiring precise repetitive motion or force control.

The trapezoid waveform command is available on all RMC75, RMC150 and RMC200 motion controllers. Controller setup, tuning and programming are performed using Delta's RMCTools software.